Saturday, March 22, 2008

Sometimes I forget how nice it is to fly over land. There's just SO much to take pictures of as this two day trip to L.A. reminded me. I had a chance to fly with a great guy, Bill, and talk small planes all the way across the country. Bill has an amphibious biplane (well, FOUR of them, actually) that he flies from his back yard. And Gadling is going forward with the Plane Answers column where I attempt to answer actual questions each week. Let's see how that goes. I'm sure the questions won't be like this one I got this week:

Great i enjoyed reading this blog am looking forward to a smallanswer....I am a production test pilot of a tranport aircraft.In one of thetests today the aircraft viciously rolls to the left with aileron &rudder trim neutral.Full left trimmer the roll is reduced but then urun out of trim.We checked the aileron posotions all ok...as perspecifications....flaps were not used.Balnce tab in the aircraft isfixed.Any thing why is it causing or what can be done...i am thinkingof gtg the CG checked...butAny wise comments please shoot

Yikes. Anyone care to guess what could be wrong? I responded with the possibility of an inop fuel gauge causing an out of balance condition, but he says that's been ruled out. He responds:

Just a guess, but is there any potential for physical distortion (damage?) anywhere on the airframe that might induce a warp or twisting action on the wings or tail surfaces? Even an imperceptible warping of the airframe has the potential to wreak havoc with stability. Has the aircraft been subject to any hard asymmetric (crosswind?) landings recently? Did someone accidentally bump into the airframe with a vehicle?

Well, after a bit of thinking, I have come up with an idea. Could there be some sort of contaminant on the left wing, resulting in less lift and more drag on that side of the airplane, causing the roll? I assume that the aircraft has been in storage for some time and so, particularly if it has been stored outside, some contamination may have built up. Also, the AN-32’s wings are positioned high on the fuselage, and so any contamination would be out of sight, unless a ladder or platform was available.